Little is known about Abdulaziz al-Omari’s life, and it is unclear whether some information refers to Omari or another person by that name. He has used birth date May 28, 1979. He is alleged to have often served as an Imam at his mosque in Saudi Arabia and is believed by American authorities[who?] to have been a student of a Saudi cleric named Sulaiman Al-Alwan, whose mosque is located in Al-Qassim Province. According to Tawfiq bin Attash, Omari was one of a group of future hijackers who provided security at Kandahar airport after their basic training at an al-Qaeda camp. During the 2000 Al Qaeda Summit in Kuala Lumpur, American authorities claim that immigration records show that a person named Abdulaziz al-Omari was visiting the country, although they say they are not sure that this was the same person. In the autumn of 2001, after the September 11 attacks, al Jazeera television broadcast a tape they claim was made by Abdulaziz al-Omari. The speaker made a farewell suicide video. In it, he reads “I am writing this with my full conscience and I am writing this in expectation of the end, which is near. . . God praise everybody who trained and helped me, namely the leader Sheikh Osama bin Laden.”

According to FBI director Robert Mueller and the 9/11 Commission, Omari entered the United States through a Dubai flight on June 29, 2001, with Salem al-Hazmi, landing in New York. He had used the controversial Visa Express program to gain entry. He apparently stayed with several other hijackers in Paterson, New Jersey, before moving to his own place at 4032 57th Terrace, Vero Beach, Florida. On his rental agreement form for that house, Omari gave two license-plates authorized to park in his space, one of which was registered to Atta. Abdulaziz al-Omari obtained a fake United States ID card from All Services Plus in Passaic County, New Jersey, which was in the business of selling fake documents, including another to Khalid al-Mihdhar. On September 10, 2001, Mohamed Atta picked up Omari from the Milner Hotel in Boston, Massachusetts, and the two drove their rented Nissan to a Comfort Inn in South Portland, Maine, where they spent the night in room 232. It was initially reported that Adnan and Ameer Bukhari were the two hijackers who had rented and driven the car. In the early hours of September 11, they boarded a commuter flight back to Boston to connect to American Airlines Flight 11. American 11 was hijacked 15 minutes after the flight departed by Omari and four other hijackers, which allowed trained pilot Mohamed Atta to crash the Boeing 767 into the North Tower of the World Trade Center as part of an attack that killed thousands of people.